In an electric arc welder, an electromechanical contactor or switch is used to direct welding power from the power source to the contact tip of the welding gun. The electromechanical contactor relies upon mechanical contacts to switch the welding current on and off, consequently, arcing at the contacts leads to degeneration of contactor performance. The degeneration of performance is exhibited as an increased contact resistance that causes an equal decrease in output power. With continued use of degraded mechanical contacts, the contactor will ultimately overheat. Such deteriorating contactors must be replaced prior to ultimate failure. If the contactor fails during an actual welding operation, the weld performed during the welding cycle may require extensive rewelding or other corrective measures.
Replacing deteriorated contacts is typically performed by replacing the electromechanical contactor device containing the deteriorated contacts. Accordingly, electromechanical contactor devices are usually in a modular form to facilitate replacement. The contactors in such devices often use a silver cadmium alloy as a contactor material. The toxic and hazardous effects of cadmium have been extensively documented. Accordingly, there exists concern over the disposal of contactor devices due to the presence of cadmium in such devices. The disposal of cadmium-containing contactor devices is of particular concern since, if a large collection of deteriorated contactor devices or modules are to be disposed, the actual cadmium content, relative to the total weight of the devices, may be relatively high. Disposal of such high proportions of cadmium may raise further issues particularly in light of future legislation against such disposals.
Accordingly, a need exists for a strategy to avoid the disposal of cadmium-containing contactor devices.